Saving reference to a ScriptableObject with JsonUtility

Questions & Answers
1

I have a data structure like the following

    [Serializable]
	public class InventoryWrapper
	{
		public CardInventory[] Data = new CardInventory[0];
	}
	[Serializable]
	public class CardInventory
	{
		public CardDefinition Definition;
		public int Quantity;
	}

CardDefinition in the example above is a ScriptableObject class. I’m using the JsonUtility.ToJson and JsonUtility.FromJson functions to save this data structure to disk and loading later.
It appeared to work fine and generates output as follows:

{
   "Data":[
      {
         "Definition":{
            "instanceID":377496
         },
         "Quantity":2
      },
      {
         "Definition":{
            "instanceID":377502
         },
         "Quantity":2
      },
      {
         "Definition":{
            "instanceID":-2897598
         },
         "Quantity":2
      }
   ]
}

This morning all my references broke and when the data is serialised FROM JSON I get null objects instead of references to my ScriptableObjects. Am I going about this in the wrong way? Can anyone help

2

Ok, that was easy.
To write GUID instead of InstanceId (i.e. preserve object references) we need to use EditorJsonUtility instead of JsonUtility